US 5,509,933 A · Medical implants of hot worked, high strength, biocompatible, low modulus titanium alloys

Abstract

Biocompatible medical implants from a high strength, low modulus, hot worked titanium alloy containing titanium, about 10-20 wt. % or 35 to about 50 wt. % niobium and up to 20 wt. % zirconium. In particular, the titanium implants have a modulus of elasticity closer to that of bone than other typically used metal alloys and does not include any elements which have been shown or suggested as having short or long term potential adverse effects from a standpoint of biocompatibility. To fabricate the alloy, it is necessary to heat to above the .beta.-transus temperature (or to a temperature in a range from 100.degree. C. below and up to the .beta.-transus), hot work the alloy, rapidly cool to below the .beta.-transus, and age the cooled alloy for a period of time to develop its strength while maintaining its low modulus (less than about 90 GPa). The alloy is suitable for a range of uses where the properties of low modulus, high strength and corrosion resistance are desirable.

Claims40

Dependent claims

A biocompatible medical implant of low modulus and high strength for implantation into a recipient's body where it is subject to varying loads imposed by physical forces and corrosive effects of body fluids, said medical implant comprising:

a metallic alloy, said metallic alloy comprising a grain structure that results from said alloy having been subjected to metallurgical treatment steps comprising:
(i) heating to a temperature in the range of from 100 .degree. C. below a B-transus temperature of the alloy to above the .beta.-transus temperature;
(ii) hot working the alloy to produce a hot worked alloy;
(iii) rapidly quenching the hot worked alloy;
and
(iv) aging the alloy at a temperature and for a time sufficient to develop strength in the alloy that is greater than an alloy of identical wt % composition that has not been subjected to said metallurgical treatment steps;
wherein the metallic alloy comprises as components:
titanium;
from about 10 to about 20 wt. % niobium;
an amount of zirconium in solution in the alloy sufficient to act as a beta stabilizer by slowing the transformation of beta;
and wherein the alloy is substantially free of toxic elements, said toxic elements being aluminum, vanadium, cobalt, nickel, molybdenum and chromium, except such amounts of said toxic elements as may occur as impurities in the components and contaminants as a result of processing, the amounts of said impurities and contaminants being insignificant to cause adverse effect on the recipient's body.

8 more elements

a metallic alloy, said metallic alloy comprising a grain structure that results from said alloy having been subjected to metallurgical treatment steps comprising:
(i) heating to a temperature in the range from about 100 .degree. C. below a .beta.-transus temperature of the alloy to above the .beta.-transus temperature;
(ii) hot working the alloy to produce a hot worked alloy;
(iii) rapidly quenching the hot worked alloy;
and
(iv) aging the alloy at about 500.degree. C. for about six hours to develop strength in the alloy that is greater than an alloy of identical composition that has not been subjected to said metallurgical treatment steps and greater than about 800 MPa while maintaining modulus of elasticity at less than about 90 GPa;
wherein the metallic alloy comprises as components:
about 74 wt. % titanium;
about 13 wt. % niobium, and an amount of zirconium in solution in the alloy sufficient to act as a beta stabilizer by slowing the transformation of beta;
and wherein the alloy is substantially free of toxic elements, said toxic elements being aluminum, vanadium, cobalt, nickel, molybdenum and chromium, except such amounts of said elements as may occur as impurities in the components and contaminants as a result of processing, the amounts of said impurities and contaminants being insignificant to cause adverse effect on the recipient's body.

7 more elements

A biocompatible medical implant of low modulus and high strength for implantation into a recipient's body where the implant is subjected to varying loads imposed by physical forces and corrosive effects of body fluids, said medical implant comprising:

a metallic alloy, said metallic alloy comprising a grain structure that results from said alloy having been subjected to metallurgical treatment steps comprising:
(i) heating to a temperature in the range from about 100.degree. C. below a .beta.-transus temperature of the alloy to above the .beta.-transus temperature;
(ii) hot working the alloy to produce a hot worked alloy;
(iii) rapidly quenching the hot worked alloy;
and
(iv) aging the alloy by the steps comprising:
(a) heating to a temperature of about 500 .degree. C. over a period of from about 1.5 to about 5 hours;
(b) maintaining the alloy at the temperature of about 500.degree. C. for about 2 to about 8 hours;
(c) cooling the alloy to ambient temperature conditions to develop strength in the alloy that is greater than an alloy of identical composition that has not been subjected to said metallurgical treatment steps;
wherein the metallic alloy comprises as components:
titanium;
from about 10 to about 20 wt. % niobium;
and an amount of zirconium in solution in the alloy sufficient to act as a beta stabilizer by slowing the transformation of beta;
and wherein the alloy is substantially free of toxic elements, said toxic elements being aluminum, vanadium, cobalt, nickel, molybdenum and chromium, except such amounts of said elements as may occur as impurities in the components and contaminants as a result of processing, the amounts of said impurities and contaminants being insignificant to cause adverse effect on the recipient's body.

11 more elements

Dependencies are inferred from the claim text.

Medical implants of hot worked, high strength, biocompatible, low modulus titanium alloys

Life of this patent

Medical implants of hot worked, high strength, biocompatible, low modulus titanium alloys

Life of this patent

Abstract

Claims40